We are interested in signal transduction pathways between the external stimuli generated at the plasma membrane and the nuclear oncogenes or other cellular and viral genes that can regulate gene expression and cell division. Such links may be provided by oncogenes located in the cytoplasm with protein kinase activity. Thus, we have investigated the possible role raf kinase may play in transmitting a signal to the nucleus to turn on or off expression of cellular and as well as viral genes. Our data suggests that the raf kinase may activate cellular oncogenes which may then activate the HIV-LTR, the HTLV-LTR as well as the immediate-early (IE) promoter of the cytomegalovirus (CMV). The activation state of raf oncogene may not only play a role in cellular transformation but it maybe important determinant of HIV, HTLV and CMV latency.